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“A short background to this work is that Nynas has assisted Petrofer in the development of a series of products aimed at heavy load applications, starting with one for a steel mill,” explains Mehdi Fathi-Najafi, Nynas’ Chief Specialist, who has helped lead the development process.
The first round of this development has resulted in the full-scale production of a high-performance grease produced by Petrofer Turkey which is now performing smoothly in various applications at a steel mill plant.
“One of the main reasons for the significantly improved performance of this new grease compared with the benchmarked product is the use of NYNAS® T 600 in the formulation. NYNAS® T 600 is a highly viscous, wax-free naphthenic oil with an excellent degree of solvency,” says Mehdi Fathi-Najafi.
Some of the characteristics offered by the new product (Petrogrease DORADA 173 EP 1½ H) include excellent low-temperature pumpability, anti-wear, and extreme-pressure properties.
“This newly developed grease has now been performing exceptionally well at a steel mill plant, and our ambition is to extend the use of this concept to other demanding applications,” comments Verda Azbazdar, Business Development Manager at Petrofer in Turkey.
In addition, the frequent and delighted comments emanating from Petrofer’s customer, the large steel plant, are an excellent testimony to the great performance of the new product.
“The secret behind the success of this development project is the dedication and trust between the people involved, both at Nynas and Petrofer, and I believe this will be of lasting benefit to the business relationship between our two companies,” emphasises Mehdi Fathi-Najafi.
Putting it to the test
• To verify the benefits of the new lubricating grease, Petrofer has used it in demanding applications at the steel mill.
• First, it was tested on bearings in the longest hot rolling line in order to evaluate the pumpability of the grease, especially during the winter. In this application, the grease pumping line is around 300 metres. Hence, during the cold season, good pumpability is the most critical characteristic of the grease used.
• The rheological behaviour of the new grease, at sub-zero temperatures, has also been benchmarked against an alternative commercial product. Figure 1. shows how the complex modulus is increased when the applied temperature is reduced. In the case of the reference grease, the sudden change of the slope at about -6°C, indicates wax precipitation of the oil used for its preparation, putting a higher demand on the flowability of the grease at lower temperature. In the case of Petrogrease DORADA 173 EP 1½ H, the increase of the complex modulus is smooth and predictable, at least down to -25°C. This positive behaviour of the newly developed grease could then be verified by using flow pressure measurements according to DIN 51805; e.g. at -20°C the required pressure for the competitive grease was 1070 mbar while for the new grease only 450 mbar!
• Second, the new grease was also used for the bearings of the finishing mill’s fastest roller in order to evaluate the behaviour of the grease at high speed. Even here, the product was shown to perform smoothly.
Mehdi Fathi-Najafi is a Senior Technical Advisor and Chief Specialist at Technical Development and Market Support, Nynas Naphthenics. He joined Nynas in 2008.